Bake the potatoes for over an hour. Take them out of the oven when you can stick a fork in them. Eat a few of them, but make sure you have at least 4 large ones left for this recipe. When they are cool, you can either stick them in the refrigerator for a day or two, or continue with the recipe right away. Cut up the potatoes in cubes, without the skin. Toss them in oil and ketchup (or tomato sauce). Sprinkle with salt and spices. Bake for about twenty minutes. Serve warm.